1. Field of the Invention
The present invention relates to a sheet member guide mechanism having a guide roller for guiding a sheet member.
2. Description of the Related Art
There is known a system for recording radiation image information of a subject such as a human body with a stimulable phosphor, and reproducing the recorded radiation image information on a photosensitive medium such as a photographic film, or displaying the recorded radiation image information on a display unit such as a CRT or the like.
The stimulable phosphor is a phosphor which, when exposed to a radiation (X-rays, α-rays, γ-rays, electron beams, ultraviolet radiation, or the like), stores a part of the energy of the radiation, and, when subsequently exposed to stimulating rays such as visible light, emits light in proportion to the stored energy of the radiation. Usually, a sheet provided with a layer of the stimulable phosphor is used as a stimulable phosphor sheet.
The above known system includes an image information reading apparatus which comprises a reading unit for reading the recorded radiation image information carried on the stimulable phosphor sheet, and an erasing unit for erasing residual radiation image information remaining on the stimulable phosphor sheet after the recorded radiation image information has been read from the stimulable phosphor sheet. The image information reading apparatus also includes a loading unit for accommodating a cassette which stores a stimulable phosphor sheet with the radiation image information of a subject being recorded thereon by an external exposure device.
When the cassette is opened, a sheet picking mechanism removes the stimulable phosphor sheet from the cassette, and the stimulable phosphor sheet is fed to the reading unit by a sheet feed mechanism. The reading unit reads the recorded radiation image information from the stimulable phosphor sheet. Thereafter, the erasing unit erases residual radiation image information from the stimulable phosphor sheet, which is then stored back into the cassette in the loading unit.
There has recently been a demand for efficiently reading the energy stored in a stimulable phosphor sheet in order to reproduce the recorded radiation image information of a subject with high image quality. Such a demand is particularly growing in the field of mammography or the like. One attempt to meet the demand is to use a transparent base in a stimulable phosphor sheet. When stimulating light is applied to the outer surface of a phosphor layer (recording surface) of the stimulable phosphor sheet, light is emitted from both surfaces of the phosphor sheet, i.e., light is emitted is from the outer surface of the phosphor layer and the outer surface of the transparent base (reverse surface). Therefore, the stimulable phosphor sheet serves as a double-side-readable stimulable phosphor sheet.
The sheet feed mechanism employs a roller for preventing the stimulable phosphor sheet from rising off a curved feed path to smoothly guide the stimulable phosphor sheet along the curved feed path. The roller has a damping member applied to an area thereof which will be contacted by the reverse surface or recording surface of the stimulable phosphor sheet. The damping member is effective to prevent the reverse surface or recording surface of the stimulable phosphor sheet from being damaged by contact with the roller.
The damping member is attached to the roller by an adhesive tape or the like. However, the adhesive tape fails to keep the damping member bonded smoothly to the entire surface of the roller. In order to bond the damping member smoothly to the entire surface of the roller, it is necessary to repeatedly detach and bond the damping member. As a result, the process of attaching the damping member appropriately to the roller is considerably complex.